In planetary automatic transmission systems, torque is transmitted from component to component within the transmission. Frequently, these components are of complex design, permitting them to serve several functions and reduce the number of components in the assembly. In such a case, the material from which the component is made is usually selected to accommodate the greatest stresses applied to this complex component. A large portion of such a component is stronger and heavier than is really necessary for the application.
In order to reduce weight, aluminum is used in place of steel where possible. Aluminum is not an appropriate material for such components as annulus gears, but it can be used for drive shells which transmit the torque between annulus gears and other supporting or torque-controlling structures within the transmission. A current version of a system which the present invention can be applied uses an annulus gear with a drive spline on its face, an aluminum drive shell with a bore to locate the annulus gear and pockets to receive the drive spline teeth, and a snap ring to retain the annulus gear within the aluminum drive shell. The aluminum component is cast and is subject to the porosities and imbalance problems common to cast components.
It is an object of the present invention to produce a torque transmission system which is light in weight and relatively inexpensive to manufacture.
Another object of the invention is to produce a torque transmission system including an annulus gear and an associated drive shell containing the gear which may be readily manufactured.